The present invention generally relates to a catheter for use in connection with the generation of monophasic action potential data for use in the study of the electrophysiology of cardiac tissue and the like. The catheter includes a contact electrode for touching the tissue to be subjected to the electrophysiological scrutiny, this contact electrode catheter including a compartmentalized tip portion. including a distal tip compartment and a proximal compartment. Each such compartment is in electrical communication with the proximal end of the catheter for electrical communication with a suitable recording device, and each compartment is filled with an electrically conductive filler material such as a thermoset resin or polymer that substantially fills each compartment in order to form a tip electrode and a lateral surface electrode. Access to the tip electrode is gained through an opening at the distal end of the catheter, while access to the lateral surface electrode is gained through an opening in the circumferential surface of the proximal compartment.
In conjunction with medical procedures such as cardiac catheterizations, it is often useful to study the electrophysiology of the tissue by obtaining and recording monophasic action potentials from endocardial sites. For example, bipolar recordings of monophasic action potentials are important in the study of drug-induced changes in the electrophysiology of the tissue. Monophasic action potential recordings are also useful for mapping the heart in order to find irritable foci. Such recordings can be used in evaluating changes in local myocardial electrical activity that are induced by pacing and/or that result from myocardial disease.
A previously developed approach for securing and recording monophasic action potentials include the application of suction electrodes to the cardiac tissue in an effort to accurately maintain the location of the electrode within a vigorously beating heart. Such suction electrodes transmit a monophasic signal that accurately reflects the onset of depolarization and the entire repolarization phase of transmembrane action potentials. Although the monophasic action potentials can be recorded accurately by the use of devices including suction electrodes, the use of suction in this context is designed to entrap cardiac tissue and can cause localized tissue damage. A response to this difficulty that has been developed includes the use of a contact electrode that eliminates the suction feature and that reports suitable monophasic action potentials by simply bringing the exploring electrode into firm approximation with the myocardial surface. Such contact electrode catheters permit easy and safe long-term monophasic action potential recording from the human endocardium during routine cardiac catheterization and the like. Monophasic action potential contact electrode catheters that have been developed in this regard utilize electrodes that are pellets of sintered silver-silver chloride.
The present invention improves upon previously known monophasic action potential contact electrode catheters and includes a compartmentalized tip portion of an elongated catheter body which preferably has torque-controlling properties in order to significantly assist in precisely locating the distal end of the catheter and in order to maintain that location for time periods, which may be extensive, during which it is desired to obtain and record monophasic action potentials. The compartmentalized tip portion includes a distal tip compartment housing a tip electrode and a proximal compartment housing a lateral surface electrode. Each of these electrodes includes a volume of conductor-loaded filler that had been injected and set and that is in electrical communication with the proximal end portion of the catheter.
It is accordingly a general object of this invention to provide an improved monophasic action potential contact electrode catheter.
Another object of the present invention is to provide a monophasic action potential catheter having a torque control body for assisting and maintaining the contact position of the catheter.
Another object of the present invention is to provide an improved monophasic action potential contact electrode catheter having an electrode structure that is relatively uncomplicated and efficient to manufacture and that is especially well suited for providing a structure that provides liquid tight sealing interfaces.
Another object of this invention is to provide an improved method for constructing a monophasic action potential contact electrode catheter.
Another object of the present invention is to provide a monophasic action potential contact electrode catheter and method of its construction which utilizes a thermosetting resin or polymer as the contact electrode.
Another object of this invention is to provide a monophasic action potential contact electrode catheter of the bipolar type in which the bipolar electrodes include filled and set thermoplastic which provides sealing surfaces that prevent blood from entering the catheter.
These and other objects, features and advantages of this invention will be clearly understood through a consideration of the following detailed description.